Assessing the impact of increased maize cropping on pollinators

In recent years there have been substantial increases in the cropped area of maize in Greater Lincolnshire largely due to its use as a feedstock for anaerobic digestion. Official figures demonstrated that between 2010 and 2013, the area cropped with maize in Lincolnshire increased by 99% and in North and North East Lincolnshire by 726%.

In order to consider the potential impact of increased maize cropping, the Nature Partnership undertook a pilot research study to understand more about how insect pollinators use arable crops. Field surveys were carried out in the summer of 2016 in maize, winter wheat, oilseed rape and peas across five Lincolnshire farm holdings.

Key findings included:

Maize fields recorded the lowest overall numbers of individuals although the average number of invertebrate groups was relatively varied compared with other crops

Maize, oilseed rape and marrowfat peas all demonstrated distinct pollinator communities while the population in winter wheat was more generalist

Crop type, amount of cultivated land within 500m, temperature and insecticide were the four main factors affecting pollinator community composition

Bare ground in maize fields was found to have potential importance for basking invertebrates

Insecticide applications were found to significantly affect not only target species such as diamond-back moth and weevils but also potentially beneficial ground beetles

Bee pollinators made up just 41 of more than 10,000 individuals recorded from the surveys

The full report from the study together with a non-technical summary can be found on our publications page.

What does this mean?

The study has highlighted the importance of maintaining not only diversity of habitats within the landscape but also the importance of maintaining a variety of different crop types. Rotations should consider which crops are being displaced by maize but also the extent of block cropping to ensure resources are available for a wide range of pollinators.

Further consideration also needs to be given to methods of supporting pollinators, and in particular bees, across a landscape scale rather than being confined to small pockets and a project to look at this in more detail was undertaken by the Nature Partnership in 2017. Increasing wild pollinators on your farm: a low cost approach is now available to help farmers make some simple improvements.

To highlight the environmental implications of growing maize and encourage farmers to consider methods to overcome them, the Nature Partnership held an event at Branston in November 2016 entitled The Growth of Maize. This included information on the agronomics of maize, diffuse pollution considerations and tips to help support pollinators on your farm – click here to view the presentations.